Analysis of Meteorological Transport Conditions and Daily Variation Characteristics of PM 2.5 Heavy Pollution Process in Hubei Province during the Winter of 2015

Q2 Engineering Acta Meteorologica Sinica Pub Date : 2018-10-25 DOI:10.11676/QXXB2018.029

白永清, 祁海霞, 赵天良, 杨浩, 刘琳, 崔春光

引用次数: 8

摘要

PM2.5 pollution remains the primary type of winter air pollution in Hubei Province, with obvious regional transmission characteristics. The meteorological conditions for air pollution during heavy pollution processes are different from those in North China, and are worth paying attention to. Using simulation results under different emission scenarios of WRF/Chem and combined with observation analysis, the meteorological transport conditions and daily variation characteristics of the PM2.5 heavy pollution process in Hubei Province from December 2015 to January 2016 were studied. The processes of horizontal transport, suspended aggregation, and downward transport of foreign pollutants were analyzed from the perspective of large-scale transport conditions and local boundary layer dynamics, and the meteorological causes of the observed afternoon PM2.5 concentration special peak in the region were explained. The results show that the outbreak of heavy pollution in Hubei is mainly caused by regional transmission. The ground observation PM2.5 extreme value corresponds to a wind speed of 8-10 m/s at 10 meters, and the boundary layer 0-1 km is a strong northerly wind transport. The extreme value of pollution transfer flux is located near a height of 400 meters, which is an important transmission channel. There is no obvious inversion in low altitude, and the heavy pollution process has "non-stationary" boundary layer meteorological characteristics. The large-scale transportation conditions for the formation of heavy pollution are as follows: abnormally strong northerly winds in the middle and lower reaches of the Yangtze River and the northern region, slow wind speeds in the southern region, causing pollutants to accumulate in the middle reaches of the plain. The higher the wind speed at the northern boundary of Hubei, the more favorable the growth of pollution transportation. Transmission pollution mainly comes from the transportation of pollution sources in the north and northeast directions, with potential source areas contributing mainly to the Yuzhong and Nanyang basins and Guanzhong regions passing through the north passage, as well as some areas such as Shandong, Anhui, and Jiangsu passing through the northeast passage. The weather causes of the bimodal structure of daily variation of PM2.5 concentration are different. The peak at 21-24 hours (Beijing time) is static pollution, and the peak at 11-14 hours is transport pollution. The transport of pollution is influenced by the height of the atmospheric boundary layer. Before sunrise, the height of the atmospheric boundary layer is relatively low, and the stratification is stable and accompanied by upward movement, causing low-level external transport to suspend and gather near a height of 400 meters; After sunrise, as the height of the atmospheric boundary layer increases, the static stable stratification is disrupted, and under the action of dry deposition, high concentration PM2.5 begins to transport downwards, forming a peak on the ground in the afternoon.

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湖北2015年冬季PM 2.5 重污染过程的气象输送条件及日变化特征分析

PM2.5污染仍然是湖北省冬季大气污染的首要污染类型，且具有明显区域传输特征，重污染过程的空气污染气象条件有别于华北地区，值得关注。采用WRF/Chem不同排放情景下的模拟结果，并结合观测分析，研究了2015年12月—2016年1月湖北省PM2.5重污染过程的气象输送条件及日变化特征，从大尺度输送条件和局地边界层动力作用分析了外来污染物水平传输、悬浮聚集和向下传输的过程，并解释了该地区观测到的午后PM2.5浓度特殊峰值的气象成因。结果表明，湖北重污染爆发以区域传输为主，地面观测PM2.5极值对应10 m风速可达8—10 m/s，边界层0—1 km为较强偏北风输送，污染传输通量极值位于400 m高度附近，为重要传输通道，低空无明显逆温，重污染过程具有“非静稳”边界层气象特征。重污染形成的大尺度输送条件为，长江中下游及北部地区偏北风异常偏强，南部地区风速减缓，使污染物在中游平原堆积，鄂北边界风速越大，越有利污染输送增长。传输性污染主要来自偏北和东北方向的污染源输送，潜在源区贡献主要为途经偏北通道上的豫中、南阳盆地和关中地区，以及途经东北通道上的鲁、皖、苏等部分地区。PM2.5浓度日变化双峰结构的天气成因不同，21—24时（北京时）峰值为静稳性污染，11—14时峰值为传输性污染。污染输送受大气边界层高度影响，日出前大气边界层高度较低，层结稳定并伴有上升运行，使得低空外来输送悬浮聚集在400 m高度附近；日出后随大气边界层高度升高，静稳层结被破坏，在干沉降作用下高浓度PM2.5开始向下传输，并在午后地面形成峰值。

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来源期刊

Acta Meteorologica Sinica 地学-气象与大气科学

CiteScore

1.46

自引率

0.00%

发文量

4250

审稿时长

6 months

期刊介绍： Journal of Meteorological Research publishes research that advances observation, modeling, and forecasting/prediction of weather and climate, as well as related topics in earth system sciences. Covers both basic and applied dynamics, physics, and chemistry of the atmosphere and its interfaces. A Springer co-sponsored journal focused on speed of submission and review, service, and integrity. Official journal of the Chinese Meteorological Society.